Dave Solberg

Helpful Gadgets: Air Flow Meter

Dave Solberg
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Duration:   2:25   mins

When something seems wrong with the cooling or heating system of an RV, it’s helpful to have an accurate description that you can provide to your mechanic to try to solve the problem. A handy gadget that every RV owner should keep in their unit is an air flow meter.

The best air flow meter is one that shows both the air flow coming out of the air conditioner/furnace and tells the temperature. When the air conditioner seems to be running inefficiently, the air flow meter can help identify specific problems, such as air not cooling or a decrease in air flow velocity. To test, turn on the unit and hold the meter up to the vent of the air conditioner. Then, try adjusting the temperature while keeping your air flow meter in front of the vent.

If you are starting to see a decrease in air flow, chances are the cold air return filter is the problem. Low air flow coming out of an air conditioning unit may be a sign that it’s time to change or clean the filters. To change the filter on a standard A/C unit, unscrew the cover from the top of the inside of the unit. You will see two filters inside the cover. Replace or clean these filters, put the unit back together, and retest the air flow. Your unit should return to normal air flow. For ducted roof air units, the filter is generally located behind the cold air return vent.

If the temperature is not what is used to be, it may be time to take the RV to your local mechanic and have the air conditioner recharged.

It is a good idea to keep an air flow meter handy so you can test the air flow and temperature of your RV’s air conditioning unit during normal operation. It will allow you to provide a mechanic with more specific details if something is not working properly.

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12 Responses to “Helpful Gadgets: Air Flow Meter”

  1. mike

    what should the temp be in relation to outside temp? that would have been helpful.as a guide line.

    • Customer Service

      Hello Mike,

      A roof AC unit can only cool down inside air by 20 degrees. So if you let the unit sit outside in the beating sun at 100 degrees outside temperatures, the inside can get well above 120 degrees and the roof AC can only cool down to 100! That is why owners need to pull down all the shades, park in a shaded area, use the awning to provide shade, and even install some window insulation products or dual pane windows. We do have an article on the site about making your roof AC run more efficient. The roof AC pulls interior air into the air return vents and extracts heat from it and pumps it back into the rig. So the cooler you can make it inside to start with is critical for the roof AC to run more efficient.

      Hope this helps,

      RV Repair Club Video Membership

  2. Richard

    You never actually said I what the temperature should be. The 67 degrees you registered on you meter seems warm. I just had my ac serviced on my truck and the reading was 32 degrees at outside temperature of 84 degrees. How much of a temperature drop should we expect from the outside temperature?

    • Customer Service

      Hi, Richard. Thanks for bringing up the temperature reference. RV roof air
      conditioners will only be able to cool the rig about 20 degrees lower than
      outside ambient temperature. That’s why it’s important during hot
      times to try to park the rig in a position where you can get some shade or
      cooler temperatures on the roof area. Newer, more efficient units
      can go down to about 25 degrees cooler but that is why you see some of the
      bigger rigs with 3 units! With that said, you should see
      temperatures coming out of the air conditioner unit at about 30 degrees
      less than outside temps, but I would use the temperature of the living
      part of the coach to check efficiency.

  3. David

    When testing temp and air flow always try to test using the same conditions (same vents open, same speed setting and same set point temperature).

  4. Gary

    Where do you get a meter like the video is showing? One that shows air flow and temp? I might add at a reasonable cost…

  5. Jim Phillips

    I don”t use Adobe Flash Player because of the numerous articles about its lack of security. Is there another program I can use?

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